package day230426;

import java.util.Scanner;

/**
 * @author 兴趣使然黄小黄
 * @version 1.0
 * @date 2023/4/26 10:53
 * 客似运来
 */
public class Main02 {

    public static void main(String[] args) {
        // 输入数据的范围为1-80 则先计算前 80 位斐波那契数
        long[] fib = new long[80]; // fib[0] 表示第一位
        fib[0] = 1L;
        fib[1] = 1L;
        for (int i = 2; i < fib.length; i++) {
            fib[i] = fib[i-1] + fib[i-2];
        }
        // 录入测试数据
        Scanner scan = new Scanner(System.in);
        while (scan.hasNextInt()) {
            int from = scan.nextInt();
            int to = scan.nextInt();
            // 计算从 from 到 to 需要的早餐数
            long breakfastCount = 0L;
            for (int i = from; i <= to; i++) {
                breakfastCount += fib[i-1];
            }
            // 打印结果
            System.out.println(breakfastCount);
        }
        scan.close();
    }
}
